EV batteries are not all the same. Researchers took apart batteries from two leading electric vehicle brands — BYD and Tesla — to try to work out which one had the best battery.
Electric vehicles (EVs) are on a roll in Australia, finally.
These silent sleek and silent, shiny cars are becoming more prevalent in daily rush hour traffic, bypassing petrol stations and challenging fossil cars (yes, that’s the phrase used by EV +owners) for road and market position.
Tesla was the top-seller in 2024, with more than 38,300 cars sold, a dip of almost 17% on 2023. BYD sold more than 14,000, increasing by almost 15% and MG sold more than 8,000 EVs — up 39% on the previous year. EVs and hybrids totalled around 90,000 for 2024, about 7% of new car sales.
BYD, an initially awkward but grows-on-you acronym, ‘Build Your Dreams,’ and Tesla, dominate the Australian market
Batteries are the core of any EV, the source of much conjecture and of the odd spot of range anxiety. Which leads to the question — which of these two industry leaders has better batteries? What’s inside?
“There is very limited in-depth data and analysis available on state-of-the-art batteries for automotive applications,” said Jonas Gorsch, a researcher at Production Engineering of E-Mobility Components at RWTH Aachen University in Germany and lead author of the study.
Gorsch and colleagues from Germany’s Aachen University decided to resolve the issue by opening the bonnets on BYD and Tesla.
They measured battery cells, worked how they were made and what from, and compared component costs and electrical and thermal performance.
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Each EV battery contains many cells — a Tesla Roadster has 6,831 lithium ion cells arranged in 11 sheets
“We were surprised to find no silicon content in the anodes of either [makes’] cell, especially in Tesla’s cell, as silicon is widely regarded in research as a key material for increasing energy density,” said Gorsch.
Both brands use lithium-ion batteries — each Tesla cell made from lithium nickel manganese cobalt oxide (called ‘NCM811’), each BYD Blade cell, lithium iron phosphate (LFP), says Gorsch. Individual Tesla cells are almost 8 times smaller than BYD’s with much greater energy density — 1.5 times by weight, 1.8 times by volume.
Tesla also uses lasers to weld electrodes — BYD uses both lasers and ultrasonics
But there are similarities — although BYD cells are much larger than Tesla cells, the fraction of “passive” cell parts, housings and other components, were similar in both.
But really, it’s all about performance — researchers found major differences in the speeds at which the two types of batteries were charging relative to their maximum capacity — called C-rate. “BYD Blade cells showed half the energy losses per volume of the Tesla 4680 cell at the same C-rate”, says. Gorsch.
The researchers concluded that Tesla’s batteries focussed on high-energy density and performance, whereas, for BYD, it was all about volume efficiency and lower-cost materials. Overall, Gorsch says, BYD’s battery was more efficient because it allowed easier thermal management.
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